Pressure hectograph copying process



May 24, 1966 m. A. NEWMAN fi fi PRESSURE HECTOGRAPH COPYING PROCESS Filed Juilgy 1-5,

%/ jf/l MASTER $HEET HECTOGRAFH DYE IMAGE POROUS VINYL. COATING cow-mmwe PRESUIEE- EXUDAQLE' 0113f DYE" SQLVEN'T.

cor-Y SHEET INVENTOR. fiau iaw A fi m vma/z United States Patent C) 3,252,414 PRESSURE HECTOGRAPH CUIYHNG PROQESS Douglas A. Newman, Glen Cove, N .Y., assignor to Columhia Ribbon and Carbon Manufacturing Co., Inc., Glen Cove, N.Y., a corporation of New Yorlk Filed July 13, 1964, Ser. No. 382,087 5 Claims. (Cl. 101-1495) This invention relates to an improved dry process for the production of multiple copies from an inscribed, typed or otherwise imaged hectograph master. This application is a continuation-in-p-art of application Serial No. 792,377, filed February 10, 1959, now abandoned.

In the conventional spirit hectograph duplicating process, a master sheet bearing images containing a soluble dyestuff is prepared with the aid of a special carbon paper whose pressure-transferable surface is placed in contact with one side of a master sheet. The other side of the master sheet is then inscribed with the original typing, writing or similar record. This produces a hectograph image in mirror reverse on the master. This imaged master sheet is attached to the drum of a conventional spirit duplicator and sheets of copy paper are fed thereto in succession. Means are provided for moistening the sheets of the copy paper with a volatile dye solvent immediately prior to their contact with the master sheet and, since the dyestutf in the images on the master sheet is highly soluble, the moist surface of the copy sheets when contacted with the images on the hectograph master dissolves some of the dye and transfers a duplicate image from the master sheet to the moist surface of the copy sheets. In this process any one of a number of desirable solvents may be used. Usually water and a solvent more volatile than water such as alcohol, methanol, acetone, or other similar solvents or combinations thereof, are used.

In the conventional spirit hectograph process, a number of disadvantages have been known to accompany the use of the ordinary wet or spirit type of copy reproduction. For example, the reproduced matter on the wet copies frequently tended to blend and back print. In some cases there was considerable offsetting of the images produced on the wet copies. Further disadvantages accompanied the difficulty of stacking the wet and softened copies which frequently curled and stuck together. In addition, the spirit duplicating machine is an expensive device which is sensitive and responsive to hot and cold variations in weather, humidity changes and the like. It also utilizes wicks which become plugged. Furthermore, the physiological'etfects of methyl alcohol, usually present in the spirit fluid, are detrimental to the hands and health of the operator. These ditficulties are significantly diminished and in many cases eliminated by the present invention.

In an effort to avoid the disadvantages of the conventional spirit process, a dry pressure process has been proposed in which the hectograph copy sheets are first treated with a composition including a liquid non-volatile dye solvent and a small amount of nitrocellulose binder material, and the dry treated copy sheets are pressed against a hectograph master sheet to pick off a portion of the master images. The transferred images are gradually dissolved by the dye solvent in the copy sheets to form copies of the subject matter of the master sheet.

While such a dry process does avoid the necessity of using volatile solvent and the other disadvantages of the spirit process, it gives rise.to other disadvantages. The most important disadvantage results from the inherent impossibility of producing a sharp clear copy by transferring undissolved dye particles to a uniform "ice.

coating containing solvent and permitting the dye to dissolve thereon. As the dye dissolves, the images spread and broaden so that they are neither sharp nor clear. This problem is eased to some extent by the incorporation of a dye precipitant with the dye solvent.

It is thus an object of this invention to avoid these and other shortcomings of the prior art.

Another object of this invention is to provide a novel dry hectograph copying process which provides instant color-formation on the copy sheets in the form of sharp clear images which do not spread or broaden without the necessity of employing a dye precipitant.

Still another object of the invention is to provide a novel dry hectograph copying process which, although not requiring the use of volatile dye solvents, functions in a manner nearly identical to the conventional spirit process. to produce copies having a high degree of sharpness and clarity.

These and other objects and advantages of the present invention will be clear to those skilled in the art in the light of the present disclosure.

In the accompanying drawing:

FIGURE 1 is a fragmentary sectional view showing in detail a master sheet and a copy sheet embodying the principles of this invention.

FIG. 2 is a sectional view showing an arrangement of a master carrying drum and a pressure roll included in an apparatus suitable for carrying out the process used herein for duplicating and transferring hectograph images from a master sheet to a succession of copy sheets of the type herein disclosed.

Referring in more detail to the figures, a hectograph 'dye bearing master 10, FIG. 1, has an image 11 produced thereon in the usual way. This is mounted on the drum 21, FIG. 2, forming part of the simplified duplicating machine. The coated copy sheet 13, FIG. 1, is shown with the pressure-responsive spongy sol-id coating 12 containing dispersed solvent material 14 releasably held or suspended in the interstices of the coating.

In the device and process used for copying or duplicating the printed matter from the master sheet illustrated diagrammatioallyin FIG. 2, master sheet 10 is shown carried by drum 21 in pressure contact with a copy sheet 13 with the coated or treated side 12 of the copy sheet facing the image 11 of the master sheet. The two sheets are then pressed between the drum 21 and roller 22 and are put into intimate contact along a transverse line, the thickness of which varies with the pressure exerted. This pressure displaces the solvent material on to the coated surface of the copy sheet and the exuded solvent is distributed over the surface of the copy sheets and dissolves off some of the dye from the imaged master sheet. This application of pressure over a very small area extending along a continuous transverse line produces a complete copy on the copy sheet.

The process of this invention with its specially coated copy sheet may be characterized as a dry type of copy reproduction. In order to produce a copy sheet having a self-contained dye solubilizing liquid available in a coating on the sheet, this invention provides a pressure responsive spony film coating for the hectograph copy sheet. This film coating is in the form of a microrecticulated or spongelike structure 'of vinyl resin having dispersed and insulated in the minute interstices thereof discrete portions of a dye-dissolving liquid. The dye solvent is a non-solvent for the vinyl resin phase and incompatible therewith sothat it separates from the binder material in the [form of pressure-exudable droplets and is reabsorbed by the spongy binder material when pressure is released.

According to the present invention, a copy sheet or similar weblike paper material is provided with a novel taneously spread and coalesces over the copy sheet surface to form a wet surface film which functions in the same manner as the wetted copy sheets in the spirit process to dissolve off a portion of the dye contained in images inscribed in mirror reverse on a hectograph master which has its imaged surface in direct contact with this self-moistened copy sheet surface. This pressurized contact between the imaged master and the self-moistened surface of the copy sheet produces an immediately readable copy of the imaged master on the copy sheet. Any surplus liquid left on the copy sheet is reabsorbed into the interstices of the spony vinyl coating as soon as the pressure is released so that the copy sheets are nearly immediately returned to their dry-to-the-touch condition.

Thus it can be understood how the present process is so similar in end result to the spirit process. In each case the master is contacted with a copy sheet having a wet surface which is not receptive to pressure-transfer of the master images so that the only dye which transfers to the copy sheet is in dissolved form and has a developed color. In each case the excess dye solvent is removed from the copy sheet surface so as to prevent any possibility of spreading of the images, such removal being effected by evaporation in the spirit process and reabsorption in the present process. The reabsorbed dye solvent is insulated within the vinyl binder so that even if it contains some dissolved dye it cannot spread or bleed this dye through the coating.

The novel copy sheet coatings of the present'invention comprise a spongy vinyl resin binder material having dispersed therein discrete droplets of liquid nonvolatile dye solvent which can be exuded to the surface of the coating under the application of pressure thereto, and can be reabsorbed into the coating by capillary action when the pressure is released.

Suitable vinyl resins include vinyl chloride, vinyl acetate and copolymers thereof, vinylidene chloride, polystyrene, acrylic and methacrylic acids, esters and amides, polyvinyl butynal, and the like.

The liquid non-volatile dye solvents used must be incompatible with the particular vinyl resin used therewith. Otherwise the dye solvent will function as a diluent or softener for the vinyl resin, will not separate therefrom in the form of discrete droplets and will not be pressure-exudable from the coating. Preferred dye solvents inolude the higher, non-volatile, liquid fatty acids .and esters such as oleic acid and butyl stearate, alcohols such as ethylene glycol and glycerine, oils such as mineral oil, chlorinated diphenyl and the like. It is also possible to use semi-solid dye solvents such as cetyl alcohol and Carbowax 4000 provided that they are mixed with compatible liquids such as glycerine to produce a liquid mixture. 7

The present copy sheet coatings are produced by dissolving 1 part by weight of the vinyl resin binder material in a suitable volatile organic solvent such as ethyl acetate, methyl ethyl ketone :or the like, adding thereto from 2 to 6 parts by weight of the dispersed phase comprising the liquid dye solvent, and applying the composition to a suitable paper or'plastic film foundation in the form of a surface coating. Upon evaporation of the volatile solvent, there results a coating which is dry-tothe-touch but which exudes the liquid dye solvent under pressure. The use of smaller amounts of dye solvent results in insuflicient exudation while the use of larger amounts gives rise to a coating which is soft and mushy. The preferred ratio by weight of dispersed phase to resin is about 4 to 1.

A number of embodiments of the particular coating exemplified in this invention for the copy sheet may be made in accordance with the following examples, which are illustrative and not limitative embodiments thereof:

Example I A continuous film former comprising a 12.5% solution of a Vinylite copolymer of vinyl acetate and vinyl chloride is prepared in an ethyl acetate solvent.

For the oil-soluble type of dye the discontinuous phase comprises the following:

parts by weight of the oil-soluble phase added to parts by weight of the Vinylite coating mixutre and the resulting dispersion coated on a copy sheet. Upon evaporation of the ethyl acetate solvent, :1 film showing dispersed oil portions in a honeycomb film structure is left in the form of a dry film on the copy sheet. The oil exudes to the surface upon subjecting the coated sheet to pressure.

Example 11 The same ingredients and procedure as outlined in Example I are used with the exception that the discontinuous phase consists of a mixture of 18 grams of oleic acid and 18 grams of butyl stearate.

To produce copies on the copy sheets of Examples I or II, a mirror reverse copy of the matter to be duplicated is formed on the master sheet by making use of a coated carbon or hectograph transfer sheet to produce on the master sheet an inscribed, typed or similar image containing the soluble dyestulf together with a suitable pressure-transferable vehicle.

This master sheet, having the image in mirror reverse thereon, is fastened to the drum of a simplified duplicating machine, the drums or surfaces thereof being adapted to distribute a pressure of about 500 p.s.i. equally over the master and copy sheets successively processed therein. The specially prepared copy sheet of Example I or II having the coated surface bearing against the imaged surface of the master sheet is firmly pressed by the rolls of the machine and in the bight between the two cylinders against the imaged master, whereupon the coated surface of the copy sheet exudes the solvent material held in the prepared coating of the copy sheet, locally in the vicinity of the images on the master, and coalesces this solvent as a wet film over the entire coating of the copy sheet, thereby moistening the images on the master with sufficient solvent to dissolve off a portion of the dye contained in these images. The result of this procedure is that a portion of the dye in the images on the master sheet is dissolved onto the copy sheet to reproduce images from the master. Repeating this process with additional copy sheets successively yields a large number of sharp clear duplicate copies.

The formulation of the liquid, non-volatile, dye-dissolving phase of the copy sheets of the present invention is well within the skill of the artisan in the light of the present disclosure. Various materials may be substituted for those specifically disclosed depending upon the nature of the dyestuff and vinyl resin used since the solubility of various dyestuffs and vinyl resins in various non-volatile solvents differs, However, in any event, the dye solvent should be substantially colorless so that its presence in liquid exuded form on the surface of the copy sheet is undetectable. Otherwise contamination of the master sheet and the apparatus would result, as well as interference with the desired contrast between the dissolved images and the color of the copy sheet.

While the invention has been described mainly with respect to the master and copy sheets being in superposed relationship at the time that pressure is exerted to exude the dye solvent, it should be emphasized that it is also possible, and in some cases preferable, to impress the copy sheet to exude the solvent and wet the surface prior to contact with the master sheet. According to this embodiment, the pressure used to cause the contact between the dye images on the master sheet and the wetted copy sheet coating can be substantially relaxed, thereby avoiding the possibility of solid portions of the dye images being pressed onto the copy sheet coating. This can be a problem when the dye images are formed of a heavy deposit of soft hectograph composition.

It is also possible to include other materials in the copy sheet coating provided that they do not interfere with the pressure exudation of the dye solvent. For instance, fillers such as titanium dioxide are preferably included to whiten the copy sheet surface and provide better contrast in the image areas. Also, if desired to insure that the copy sheets are even cleaner-to-the-touch, a dye precipitant such as a tungsten or molybdenum compound maybe included in the copy sheet coating.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. The dry method of duplicating from an imaged master sheet having soluble hectograph dyestufl? images thereon in the absence of conventional spirit duplicating fluids, which comprises superposing said master sheet with its hectograph dyestuff images in surface contact with the dry-surface coating on a copy sheet, said dry-surface coating having a porous, sponge-like structure and comprising about 1 part by weight of a vinyl resin having dispersed within the pores thereof from about 2 to about 6 parts by weight of droplets of a pressure-exudable oily liquid which is a solvent for the hectograph dyestuif of said images and a non-solvent for and incompatible with the vinyl resin, and applying sufficient pressure to said superposed sheets to exude the liquid solvent from said coating and distribute it as a wet solvent film over the entire copy sheet coating, whereby said wet solvent film dissolves hectograph dyestutf from said images to form duplicate non-spreading images of immediate intensity on the copy sheet coating but is not receptive to the pressure-transfer of solid portions of the images from the master sheet.

2. The method according to claim 1 wherein said pressure is applied to the copy sheet while it is in contact with said master sheet.

3. The method according to claim 1 wherein said pressure is applied to the copy sheet before it is contacted with said master sheet.

4. The dry method of duplicating from an imaged master sheet having soluble hectograph dyestuif images thereon in the absence of conventional spirit duplicating fluids, which comprises superposing said master sheet with its hectograph dyestutl images in surface contact with the dry-surface coating on a copy sheet, said drysurface coating having a porous, sponge-like structure and comprising about 1 part by weight of a vinyl resin having dispersed within the pores thereof about 4 parts by weight of droplets of a pressure-exudable oily liquid which is a solvent for the hectograph dyestutf of said images and a non-solvent for and incompatible with the vinyl resin, and applying sufficient pressure to said superposed sheets to exude the liquid solvent from said coating and distribute it as a Wet solvent film over the entire copy sheet coating, whereby said wet solvent film dissolves hectograph dyestulf from said images to form duplicate non-spreading images of immediate intensity on the copy sheet coating but is not receptive to the pressure-transfer of solid portions of the images from the master sheet.

5. The dry method of duplicating from an imaged master sheet having soluble hectograph dyestufi images thereon in the absence of conventional spirit duplicating fluids, which comprises superposing said master sheet with its hectograph dyestuflf images in. surface contact with the dry-surface coating on a copy sheet, said dry-surface coating having a porous, sponge-like structure and comprising about 1 part by weight of a vinyl chloride-vinyl acetate copolymer resin having dispersed within the pores thereof about 2 to 6 parts by weight of droplets of a pressureexudable oily liquid including oleic acid and butyl stearate which are solvents for the hectograph dyestuif of said images and non-solvents for and incompatible with the vinyl resin, and applying suflicient pressure to said superposed sheets to exude the liquid solvent from said coating and distribute it as a Wet solvent film over the entire copy sheet coating, whereby said wet solvent film dissolves hectograph dyestufi from said images to form duplicate nonspreading images of immediate intensity on the copy sheet coating but is not receptive to the pressure-transfer of solid portions of the images from the master sheet.

References Cited by the Examiner UNITED STATES PATENTS 673,400 5/1901 Kretschm ann 117152 680,637 8/1901 Brown.

901,824 10/1908 Brias et al 101-1494 2,086,011 7/1937 Whitmore 10l149.4 X 2,337,737 12/1943 Champion 101-1495 2,348,128 5/1944 Groak.

2,581,186 1/1952 Green 117152 3,034,428 5/1962 Ellam 10l-l49.5 X 3,055,297 9/1962 Leeds 101327 DAVID KLEIN, Primary Examiner.

J. A. BELL, Assistant Examiner. 

1. THE DRY METHOD OF DUPLICATING FROM AN IMAGED MASTER SHEET HAVING SOLUBLE HECTOGRAPH DYESTUFF IMAGES THEREON IN THE ABSENCE OF CONVENTIONAL SPIRIT DUPLICATING FLUIDS, WHICH COMPRISES SUPERPOSING SAID MASTER SHEET WITH ITS HECTOGRAPH DYESTUFF IMAGES IN SURFACE CONTACT WITH THE DRY-SURFACE COATING ON A COPY SHEET, SAID DRY-SURFACE COATING HAVING A POROUS, SPONGE-LIKE STRUCTURE AND COMPRISING ABOUT 1 PART BY WEIGHT OF A VINYL RESIN HAVING DISPERSED WITHIN THE PORES THEREOF FROM ABOUT 2 TO ABOUT 6 PARTS BY WEIGHT OF DROPLETS OF A PRESSURE-EXUDABLE OILY LIQUID WHICH IS A SOLVENT FOR THE HECTOGRAPH DYESTUFF OF SAID IMAGES AND A NON-SOLVENT FOR AND INCOMPATIBLE WITH THE VINYL RESIN, AND APPLYING SUFFICIENT PRESSURE TO SAID SUPERPOSED SHEETS TO EXUDE THE LIQUID SOLVENT FROM SAID COATING AND DISTRIBUTE IT AS A WET SOLVENT FILM OVER THE ENTIRE COPY SHEET COATING, WHEREBY SAID WET SOLVENT FILM DISSOLVES HECTOGRAPH DYESTUFF FROM SAID IMAGES TO FORM DUPLICATE NON-SPREADING IMAGES OF IMMEDIATE INTENSITY ON THE COPY SHEET COATING BUT IS NOT RECEPTIVE TO THE PRESSURE-TRANSFER OF SOLID PORTIONS OF THE IMAGES FROM THE MASTER SHEET. 